From f09398cec665259a4c2f96726680fbd3b0a3bac3 Mon Sep 17 00:00:00 2001 From: Etienne Dechamps Date: Wed, 4 Jul 2012 15:56:40 +0200 Subject: [PATCH] Use /sys/module instead of /proc/modules. When libzfs checks if the module is loaded or not, it currently reads /proc/modules and searches for a line matching the module name. Unfortunately, if the module is included in the kernel itself (built-in module), then /proc/modules won't list it, so libzfs will wrongly conclude that the module is not loaded, thus making all ZFS userspace tools unusable. Fortunately, all loaded modules appear as directories in /sys/module, even built-in ones. Thus we can use /sys/module in lieu of /proc/modules to fix the issue. As a bonus, the code for checking becomes much simpler. Signed-off-by: Brian Behlendorf Issue #851 --- lib/libzfs/libzfs_util.c | 24 +++++------------------- 1 file changed, 5 insertions(+), 19 deletions(-) diff --git a/lib/libzfs/libzfs_util.c b/lib/libzfs/libzfs_util.c index 982a6f05fd97..5618a5cd307f 100644 --- a/lib/libzfs/libzfs_util.c +++ b/lib/libzfs/libzfs_util.c @@ -608,27 +608,13 @@ libzfs_print_on_error(libzfs_handle_t *hdl, boolean_t printerr) static int libzfs_module_loaded(const char *module) { - FILE *f; - int result = 0; - char name[256]; + const char path_prefix[] = "/sys/module/"; + char path[256]; - f = fopen("/proc/modules", "r"); - if (f == NULL) - return -1; + memcpy(path, path_prefix, sizeof(path_prefix) - 1); + strcpy(path + sizeof(path_prefix) - 1, module); - while (fgets(name, sizeof(name), f)) { - char *c = strchr(name, ' '); - if (!c) - continue; - *c = 0; - if (strcmp(module, name) == 0) { - result = 1; - break; - } - } - fclose(f); - - return result; + return (access(path, F_OK) == 0); } int